Variable-capacity compressor



1,6 ,4 July 19,1927 M. RIESNER .36 39 VARIABLE CAPACITY COMPRESSOR Filed Nov. 10, 1926 2 Sheets-Sheet 1 Mum-ms RIESNERQ NTOR ATTORNEY 1,636,439 y 1927- M. RIESNER VARIABLE CAPACITY COMPRESS OR Filed Nov- 10. 1926 2 Sheets-Sheet 2 T INTAKE III/i I I'll/I "III/II MICHAEL R|E NER.-

l NTOR 7 ATTORNEY was July 19.1927.

UNITED, STATES.

r 1 3,01 OIIICINITATI, OHIO, ASSIGNOB TO WORIHINGTON rm AND 1 CORPORATION, OF NEW YORK, N. Y., A CORPORATION O! VIRGINIA PATENT. OFFICE- vmmLn-oaracmr comansson Application fled'llovember 10, 1926. Serial in. 147,540.

This invention relates to air or gas compressors and more particularly to means for automatically unloading the compressor, in a graduated manner, when the receiver pres- 6 sure rises to pro-determined degrees and loading it in a raduated manner as the re ceiver pressure alls, and the-primary object of the invention is to provide an ap aratus of this type which will be economica in eration, provide for a relatively high 'e ciency com ressor and one which will be relatively slmple. in construction and consequently,cheaper to manufacture than those heretofore'used, and especially suitable for 16 com ressors of constant speed.

T e present invention contemplates the use in a variable capacity compressor, of clearance chambers and by-pass which opens into the suction port of the compressor, thereby preventing excessive heating when the compressor is running or operating at zero capacity, together with suitable pressure 0 erated control apparatus to permit t e graduated unloading and loading of the compressor cylinder, for permitting its operation under various pre-determined percentages of its full capacity.

For a full understan ing of the invention, a detailed description of constructions embodying the same in preferred form will now be given in connection with the accompanying drawin forming a part of this specification, an the features forming the invention then specifically. pointed out in the claims.

In the drawin Fi re 1 is a iagrammatic' section of th varia le capacity compressor constructed in accordance with this invention.

Figure 2 is a cross section, through the compressor taken on the line 2-2 of Figure 1.

Figure 3 is a section through a modified. v. I

- the capaclty of the clearance chamber 11 1s form of the compressor.

Figure 4 is a cross section throu h the modified form of the compressor ta en on the line 1-4 of Figure 3.

Referring more particularly to the drawings, the: improved compressor comprises a cylinder 1 having a, head end 2, a crank end 3 with the usual type of piston 4 mounted for reciprocatory movement within the cylinder for the compression of the air or as.

In the construction illustrated in igure '1 of the drawings,clearance chambers 10 and 11 are provided which are of unequal capacity, the clearance chamber 11- havm a greater capacity than the clearance cham er 10. However, this arrangement maybe re versed without departing from the spirit of cylinder 1 and the clearance chamber 10, and this 1port is closed by valve 13. A port 14, Whic is controlled by the valve'15 establishes communication between the head end 2 of the c Butler 1 and the clearance chamber 11. T e clearance chambers 10 and 11 have communication through ports 16 and 17 respectively with the by-pass 18 which the invention. A port 12 establishes com-" I mumcation between the crank end 3 of the extends to and has communication with the suction port or intake 18' of the 'air compressor.

The valve 13 is actuated by a ressure o erated piston 19 which is mov in its 0 inder 20 by receiver pressure while the va vs 15 which controls the port 14, and the valve 21 which controls the ports 16 and 17 are actuated by pressure operated pistons 22 and 23 respectively.

Operation of thepistons 19, 22 and 23 is automatically controlled by a control apparatus of approved construction, such as the control apparatus illustrated and described in my co-pending application, Serial #136,008 and prior Patents #1,579,781 and #1,579,782, the istons being operated to close the valves by low pressure fluid admitted through pipes 28 and -30 from the intermediate receiver-or other suitable sup- P The clearance chambers 10- and 11 may be. of any desired capacity so as to unload and load the cylinder 1 in the steps required, but assuming that the capacity of the clearance chamber 10 is such as to unload one-half of the crank end 3 of the compressor, while 25 and move the piston outwardly, unseating the valve 13 and opening the crank end of the cylinder 1 to the clearance pocket 10. The compressor will then operate at capacity.

On a further increase of receiver pressure the piston 22 will be moved outwardly by fluid under pressure admitted through the pipe 26 and port 27 for unseating the valve 15, which will open the head end 2 of the cylinder to the clearance chamber 11, and at the same time the pressure fluid will be cut.

off from pipe 24 so that the lower pressure the clearance pockets l0 and 11 and the b pass 18, at which time the compressor will operating at 25% capacity.

A further decrease in receiver pressure will out off the supply of fluid under pressure against the inner surface of the'piston 19 and this pistonwill be operated through the lower pressure fluid admitted through the plpe 28 to close the valve 13 and permit the compressor to operate at 50% capacity or with the head end wholly unloaded.

As the receiver'pressure further decreases the pressure on the inner side of the piston fluid from pipe 28 will seat the valve 13 and 22 is cut ofl' and the valve 15 is seated; howclose the crank end of the cylinder from the clearance chamber 10, thus permitting a 50% unloading of the cylinder, by the clearance chamber 11 at which time the compressor will operate at 50% capacity.

On a still further increase of receiver pressure the fluid under pressure, admitted through the pipe 24 and port 25 will again operate the piston 19 to unseat the valve 13 which will open the crank end 3 of the cylinder 1 to the clearance pocket 10. At this time the head of the cylinder will be completely unloaded while the crank end will be one-half unloaded and the compressor will operate at 25%- of its capacity.

Should the receiver pressure rise or increase still further, the fluid under pressure will be admitted through the pipe 29 on the inner side of the piston 23 and will move this piston outwardly, unseating the valve 21 which will open the clearance pocket-s 10 and 11 to the suction port of the compressor through the by-pass 18 allowing the air to move back and forth from one end of the cylinder to the other, at which time the compressor will be completely unloaded and will operate at zero capacity. The opening of the clearance pockets 10 and 11 to the Suction port of the compressor will prevent such excessive heating as might be encountered due to the same air being churned back and forth in the compressor, if completely unloaded by clearance pockets and by-pass only, because as constructed fresh cool air is drawn into and expelled from the cylinder on each stroke.

Decrease inreceiver ressure reverses the operation above descri ed, the compressor being loaded in a graduated manner in the same proportions of its' vfull capacity as those in which it is unloaded; i. e. upon decrease in receiver pressure the admission of from the inner side of the piston the relatively low pressure which is admitted to the piston through the pipe 30 will seat the valve 21 cutting off communication between ever, at the same time that the valve 15 is seated, the' pressure is again admitted to the inner side of the piston 19 so that the valve 13 is opened at the same time that the valve 15 1s closed, and this permits the compressor to operate at 75% capacity, owing to the fact that the crank end 3 is one-half unloaded by the clearance chamber 10. The final step of loading of the compressor is through the closing of the valve 13 in the same manner as above described, which completely cuts off the cylinder 1 from communication with the clearance chamber 10 and allows the compressor to operate at capacity.

In Figure 2 of the drawings a modified construction of the compressor is shown in which clearance chambers 50 and 51 are cylinder 54 through the ports 55 and 56 (respectively. The clearance chambers 50 and "51. have communication with a by-pass '57 through ports 58 and 59 respectively and the by-pass 57 has communication with the suction port or intake 57 of the compressor.

A valve 60 controlling the port 55 and a valve 61 controls the port 56. The valves 60 and 61 are actuated by pressure 0 erated pistons 62 and 63 respectively, which move in cylinders 64 and 65. Fluid under pressure is admitted against the inner sides of the piston 62 and 63 throughpipes 66 end 67 for operating the pistons to unseat the valves 60 and 61, and admittance of the fluid under'pressure into the cylinders 64 and 65 against the inner sides of the pistons 62 and 63 is controlled by a control apparatus of approved construction, such as that disclosed in my co-pending application and prior patents above mentioned.

The ports 58 and 59 are controlled by valves 68 and 69 which are operated by pressure operated pistons 70 and 71 movable in cylinders 72 and 73. Fluid under pressure is admitted to the cylinders 72 and 73 against the inner sides of the pistons 70 and 71 through pipes 7 4: and 75, and such admission of fluid under pressure is controlled by the same control apparatus, which controls the admittance of fluid under pressure to Ill:

- fluid is admitted to each of the cylinders 64,

65, 72 and 73 against the outer sides of the pistons 62, 63, and 71 for seating the valves 60, 61,68 and 69 when the flow of fluid under pressure against the inner sides of the respective pistons is cut off.

The clearance chambers 50 and 51 may be of any desired capacity so as'to unload and load the cylinder 54 in the steps required, but assuming that the capacity of each clearance-chamber is such as to provide a onethird unloading of the cylinder 54, the op-..

eration of the construction shown and above tion or arrangement of parts shown but that these may be modified widely within the invention defined by the claims.

What is claimed is i 1'. In a variable capacity compressor, the

combination with a cylinder, ot a plurality pressure operated means for partially unoading said cylinder by said clearance chambers and for wholly unloading the cylinder I by said clearance chambers and by-pass.

2. In a variable capacity compressor, the

described is as follows: Assuming that the combination with a cylinder, of clearance compressor is operating at full capacity, an increase in receiver pressure above that for which the apparatus is set-will operate the pistons 62 and 63 for opening the valves 60 and 61, which opens the crank end52l' and-head end 53 of the cylinder to the clearance chambers 50 and 51, at which time the compressor will be operating at 66% capacity. Upon a further increase in receiver pressure the valve 68=will be opened v by operation of the piston 70 which will bypass the crank end 52 of the cylinder through the clearance chamber 50 and by-pass 57 to the suction port of the compressor, at which time the compressor will operate at 33% capacity.

On a still further increase in receiver pressure the valve 69 will be opened which will 0 en the clearance chamber 51 to the by-pass 57 and thus by-p'ass the head end of the cylinder 54 through the clearance chamber 51 and by-pass 57 to the suction port of the cylinder, at which time the compressor will operate completely unloaded or at zero capacity.

Decrease in receiver pressure reverses the above described operation, the compressor being graduall loaded in the same proportions of its ful capacity as those in which it is unloaded.

' By variance of the control apparatus, the steps of unloading the compressor as. just above described maybe varied and instead of opening the valves 60 and 61 simultaneously to open the crank and head ends of the cylinder to the clearance pockets 50 and 51, these valves may be operated in sequence which will add an additional step to the unloading of the compressor or if desired, the control apparatus may be arranged to operate the valve 68 and 69 simultaneously in lieu of in sequence which would subtract a step in the operation of unloading and loadin the compressor from the steps specifical ly described above, and it is to be understood that such variations may be made without departing from the spirit of this invention.

It will "be understood that the invention is not to be limited to the specific construcchambers, a by-pass between the ends of the cylinder and to the suction, port of the cylinder, and pressure operated means for partially unloading said cylinder by said clearance chambers and wholly unloading the cylinder by opening said by-pass.

3. In a variable capacity compressor, the combination with a cylinder, of a clearance chamber for partially unloading the crank end of said cylinder, a by-pass port having communication with the suction of the cylinder and with said clearance chamber for wholly unloading the crank end of the cylinder.

4. In a variable capacity compressor, the combination with a cylinder, of a clearance chamber for partially unloading the crank end of said cylinder, a by-pass port having communication with the suction of the cylby-pass port having communication with said clearance chambers and with the suction port of the compressor, and pressure operated means for opening the ends of the cylinder to said clearance chambers in sequence and for simultaneously opening said clearance chambers to said by-pass.

6. In a variable capacity compressor, the combination with a cylinder, of a plurality of clearance chambers, pressure operated means for partially unloading said cylinder gradually by opening of the clearance chambers to said cylinder, a by-pass having communication with the suction of the cylinder and with said clearance chambers, and pressure operated means for opening said clearance chambers to said by-pass.

7. In a variable capacity'compressor, the combination with a cylinder, of a plurality of clearance chambers, ressure operated means for partially unloa ing said cylinder gradually by successive opening ofthe clearance chambers to said cylinder, a by-pass having communication with the suction of the cylinder and with said clearance chambers, and pressure operated means for simultaneously opening said clearancechambers to said by-pass.

8. In a variable capacit combination with a cylin er, of a plurality of clearance chambers, pressure operated means for partially unloading said cylinder gradually by opening of the clearance chamers to said cylinder, 21 by-pass having communication with the suction of the cylinder and with said clearance chambers, and pres sure operated means for successively opening said clearance chambers to said by-pass.

9. In a variable capacity compressor, the combination with a cylinder having an incompressor, the

take, of a clearance chamber,.a by-pass havmg communication with said chamber and with the suction of the cylinder, a pressure operated valve for opening said chamber to the cylinder and ,a second pressure operated valve for opening said chamber to said bypass.

' operate-d valves for controlling connection of said clearance chambers with said cylinder and pressure operated valves for controlling connection of said chambers with said bypass.

10. Ina double acting variable capacity 7 In testimony whereof I afiix my signature. 40

MICHAEL RIESNER. 

